Exhaust tube crack-off device



April 7, 1954 A. P. RUSSELL ET AL EXHAUST TUBE CRACK-OFF DEVICE Filed Oct. 30, 1951 ln'v-en tofsz Av thur P. RusseLL, John HHoLLope kma,

Their- A IFtQFYwe Patented Apr. 27, 1954 EXHAUST TUBE CRACK-OFF DEVICE Arthur P. Russell,

Maple Heights, and John H.

Hollopetre, Mayfield Heights, Ohio, assignors to General Electric Company, a corporation of New York Application October 30, 1951, Serial No. 253,922

3 Claims.

Our invention relates to apparatus for cracking-oif an excess end portion of a vitreous exhaust tube extending from a mount for a lamp, radio tube or other electrical device of similar construction. Our invention relates in particular to automatically operated apparatus for cracking-off an end section of an exhaust tube extending from a stem of the so-called tipless type and constituting the main supporting element of mounts used in incandescent and fluorescent lamps and many other electrical devices.

The cathode mount for fluorescent lamps, for instance, is manufactured by a method and means whereby an exhaust tube of relatively long length is required on the stem tube of the mount. However, midway in the manufacture of the fluorescent lamp an exhaust tube of such a long length is no longer required and, in fact, is objectionable in that it is easily broken and in that it projects from the end of the fluorescent lamp, making the handling thereof more difficult. Damaged and broken exhaust tubes prevent the proper coupling of manufacturing apparatus to the lamp and require a lamp damaged in this manner to be discarded.

One object of our invention is to provide apparatus for cracking-off an excess end portion of a vitreous exhaust tube extending from a stem of a mount and to effect the crack-01f in a manner causing a clean break across the exhaust tube at a definite position along its length. The apparatus removes the excess portion of the exhaust tube not required in subsequently occurring manuiacturing operations and produces a cut end on the remaining end of said tube on the mount which renders it suitable for connection to other manufacturing apparatus and, at a later interval, to be sealed or tipped-off.

Another object of our invention is to provide effective and relatively inexpensive automatically operating apparatus for cracking-off an end portion of an exhaust tube extending from the vitreous stem of a mount, the apparatus being particularly suited to be incorporated in existing lamp making apparatus and to effect the crackoii of the exhaust tube while the mount is retained by the relatively flexible chain type conveyor of said apparatus. In a preferred embodiment of the invention, the mounts are carried during the course of their manufacture to means for scoring the exhaust tubes at the crack-elf point and are then carried to operative relation to means for applying a bending force to said exhaust tubes to cause said tubes to crack-ofi. The latter operation occurs at a time when the mounts are retained in heads of a chain type conveyor and, because of the construction of said heads, are adapted to be tilted to a wedged position wherein pressure against the exhaust tubes of the mounts can create tension in the scored area thereof.

Other objects and advantages of our invention will appear from the following detailed description of a species thereof and from the drawing.

In the drawing, Fig. 1 is a plan view of adjacent portions of two interconnected conveyors in respective ones of which the exhaust tube scoring and crack-oh means of the invention are incorporated; Fig. 2 is a side elevation of the end portion of the conveyor comprising the crack-01f means, the view being modified by the removal of the near side of the conveyor chain to more clearly show said crack-off means; Fig. 3 is a perspective view, on a larger scale, of one of the heads of the crack-off conveyor and adjacent portions of the chain and supporting rails therefor; and Fig. 4 is a perspective view of the actuating means and the associated support means at the end of the conveyor opposite from the crackofi means.

Referring to Fig. 1 of the drawing, the scoring operation, which is the first step in the removal of an excess end portion of an exhaust tube of a mount, is shown as occurring at station A along a mount conveyor I, whereas the crack-cit operation, which completes the removal of said excess portion, is shown occurring at station C along a second mount conveyor 2 carrying the mount in a subsequent interval in the manufacture. The station A and the following station 13 represent work stations to which the mount 3 is indexed in the course of movement of the mount conveyor I of cathode mount making apparatus of the type disclosed in Flaws Patent 2,380,742 dated July 31, 1945, and assigned to the assignee of the present invention. The mount 3 is retained at all stations of both conveyors and 2 in an inverted position as shown in Fig. 2 with the vitreous exhaust tube 4 projecting upwardly from the flared vitreous stem tube 5 and with the cathode assembly 6 located directly below the stem tube 5. The scoring operation takes place at station A of conveyor I when the sharp edged metal disc 1 on the spindle 8 of a high speed electric motor 9 is moved against a portion of the exhaust tube 4 for an instant and causes a notch or score it) (Fig. 2) to be made therein at a point adjacent the flared rim H of the stem tube 5.

No further operations relating to the present invention occur until the mount 3 is advanced to station B of conveyor 1 at which station said mount 3 is transferred into one of the heads l2 of the chain type conveyor 2. The transfer is effected at the limit of an end-foremost translational movement of the conveyor 2 (which is for the most part representative of a conveyor disclosed in the aforesaid Flaws Patent 2,380,742) when a head i2, then located at the end of the conveyor 2, is advanced to an extent that the jaws l3 and Hi are in gripping relation to the exhaust tube 4 and the tines of theforked or bifurcate end of the holder l5 (Figs.- 2 and 3) are un der the fiared rim H of the stem tube 5. The release of the mount 3 by the conveyor I com pletes the transfer operation when said mount 3 drops slightly so that the flared rim I l of the stem tube Ei comes to rest upon the holder l5.

The next step in the operation of the apparatus is a retraction of the conveyor 2 bodily to the right to the position it appears in Fig. 1 and is the result of corresponding movement of the sprockets l6 and ii at the end turns of the chain it supporting the heads l2. The retraction movement also effects an indexing movement of the conveyor 2 to carry the heads i2 in a clockwise direction (Fig. l) thereabout and, accordingly, advances a head l2 containing a mount 3 away from the end position thereof while an empty head 22 is advanced thereto. The index is brought about by the relation of the sprocket i8 and the support shaft l9 therefor and occurs when the movement of the conveyor 2 causes the relative movement produced in the arm and pawl 2! to turnthe ratchet wheel 22 on a lower portion of the shaft 9. The arm 20, which is connected through bar 23 to a stationary part of the apparatus and which is pivoted on the shaft l9, pulls the pawl 21 back around the ratchet wheel 23 to another notch therein during the advance of the conveyor 2 and, accordingly, does not cause the chain it to be indexed at such times.

During the passage of the heads l2 along the straight runs of the conveyor 2, the chain it is guided in its direction of travel by the rails 2d and 25 on opposite sides of each run, and the mount holders it?- slide along the top surfaces of said rails 24 and 25. A bracket-shaped member as, of which the holder it? is a part, provides the support for the exhaust tube retaining jaws l3 and it which are pivoted upon the bolt 21 and which are closed against the exhaust tube 4 by the contraction: force of a spring 28 extending between ears on the jaws. A tongue 29 on the bracket 2%, and between the jaws l3 andi4, centers said jaws l3 and Hiover the stem tube 5 of the mount 3 and the holder I5.- The opposite ends of the conveyor 2 are caused to advance and retract correspondingly since the opposite ends of the" guide rails 24 and 25 are fastened to the movable support 30 (only partially shown) for the sprocket l6 and shaft l9 at the loading end thereof and tothe movable support 31 for the sprocket I? and the shaft 32 at the opposite end thereof. As shown in Fig. 2, the support 3'! is restricted to a definite path of movement by the engagement of the rollers 33 and 34 thereon with the top surface and a channel way res'pectively, in the block 35 of the bracket 38 on the upper end of the fixed standard 31.

The translational movement of the conveyor or carrier 2 may be effected by actuation of the assembly of rails 24, 25 and supports 30, 31 by cam actuated means- (Fig. 4) comprising a earn 50 which may be mounted on the drive shaft 5% of the conveyor 1. A cam follower lever 52 is ac tuated by the track 53 in cam 50 through a roller to at one end thereof, and is pivoted about a stationary shaft 55 to actuate a link 56 connected to support member 36 to impart the translational movements thereto in proper timed sequence with actuation of the conveyor 1.

The crack-off operation of the invention occurs during the advancing translational movement of said conveyor 2 toward the loading position when the head l2 at station C is carried toward an abutment or crack-off member in the form of the stationary finger 38 to press the upper end portion of the exhaust tube A against said finger 3%. The advancing motion in the conveyor 2 brings the end of the stationary finger til against the side" of the exhaust tube 5 containing the notch or score 10 (Fig. 2) and now facing toward the center of the conveyor 2 against its opposite position in the first conveyor l, and produces a bending pressure against said exhaust tube t which applies a rupturing strain in the notched area.

The success of the operation is dependent upon proper wedging of the mount 3 at a fixed position in the holder if: during the initial moments of the movement of the exhaust tube :3 against the finger 38 when the mount 3 is tilted thereby to an extent that the rim l l of the stem tube 5 against the overhanging lip 39 of the holder iii. The pressure of the finger 38 against the upper portion of the exhaust tube 4 first forces said exhaust tube i from between the jaws l3 and and then tilts the mount 3 to an extent that the in). l i of the stem tube 5 is forced against the lip 39 of the holder to and the supporting legs at for said lip 39. All portions of the holder l5 remain in fixed position during the crack-off operation since the back edge ti of the lip 39 bears against an ear 26 on the upstanding portion of bracket 2b of the holder l5 and said bracket 2% is backed by the shoulder 62 of the collar 43 on the sprocket shaft 32 at such times. The sudden break of the exhaust tube 4 throws the free end portion thereof out from the mount 3 to a position where it falls clear of all portions of the apparatus and the mount 3 is prevented from jarring out of the holder l5 by a stationary guard it located opposite the stem tube 5 at a position adjacent the end of said holder l5.

Inasmuch as the lip 35 must be of a size to match the flared stem tube 5 of the mount 3 and must be replaced with another of different size if a mount 3 having a different stem tube is being handled, said lip 39 is provided with legs 40 which can be sprung outward to separate it from the holder to. Means are also provided in the apparatus to render the crack-off means inoperative,

a condition which is sometimes desirable. Said means is in the form of a hinge pin 45 on the supporting arm 46 for the finger 38 and allows said finger 38 to be swung back to a rest position on the support arm 45. In its normal position, the finger 38 rests upon the extending end portion 41 of the support arm 46 and remains at a fixed position since the rod d8 holding the support arm 46 is mounted in the bracket 36 on the end of the support standard 31.

Although a preferred embodiment of the invention has been described specifically, it will be understood that the invention is not limited to the specific construction and arrangement of parts shown, but that they may be modified within the spirit and scope of the invention as defined in the appended claims.

What we claim as new and desire to secure by Letters Patent 01 the United States is:

1. In combination, a conveyor comprising an endless chain carrying a plurality of holders each having a horizontal bifurcate portion adapted to support the flared upper end of a stem tube of a mount having an exhaust tube projecting upwardly therefrom, each of said holders also ineluding a horizontal overhanging lip portion above and to the rear of said bifurcate portion. so as to overlie a portion of the rim of the flared end of a stem tube in said holder, means to effect translational motion of said conveyor to advance it toward and retract it away from a loading position, means to index said chain about the conveyor during the retraction of the conveyor, an abutment finger means located above one of the positions occupied by said holders and in the path of movement of the upper end of an exhaust tube of a mount carried by the holder at said one position during the advancing translational movement of the conveyor to first cause the mount to be tilted and its flared end wedged in its holder against the said lip portion thereor" and to then cause the exhaust tube to be bent and cracked ofi.

2. In apparatus of the class described, a carrier, a plurality of stem holders mounted at the periphery of said carrier, each of said stem holders comprising a generally U-shaped bracket member arranged with its legs extending horizontally and one above the other and projecting outwardly from the carrier, the lower leg of said bracket being slotted at its free end to receive a lamp stem having a flared upper end rested on said lower leg and also having a glass exhaust tube projecting from said stem upwardly beyond said flared end, a pair of spring-closed jaws mounted on the upper leg of said bracket and aligned with the slot in said lower leg to resiliently grip the said exhaust tube, and a wedge member in the form of a readily-detachable clip secured to said lower leg and having a horizontal body portion spaced above said lower leg to be just above the flared upper end of the stem in said holder and abutting against the upstanding portion of said bracket which connects said legs, said body portion having deformable leg portions extending downwardly from opposite sides thereof and shaped to clip onto opposite sides of the lower leg of said bracket to the rear of the said slot therein, an abutment finger means located adjacent the path of movement of the holders and inwardly of the periphery of said carrier, and

means to effect relative horizontal movement of a holder and said abutment means to bring the exhaust tube of a stem in said holder into engagement with said abutment means to first tilt the stem so that its flare becomes wedged between the said lower leg of the holder and said wedge member and to crack off the said exhaust tube upon continuation of said relative movement.

3. In apparatus of the class described, a carrier, a plurality of stem holders mounted at the periphery of said carrier, each of said stem holders comprising a generally U-shaped bracket member arranged with its legs extending horizontally and one above the other and projecting outwardly from the carrier, the lower leg of said bracket being slotted at its free end to receive a lamp stem having a flared upper end rested on said lower leg and also having a glass exhaust tube projecting from said stem upwardly beyond said flared end, a pair of spring-closed jaws mounted on the upper leg of said bracket and aligned with the slot in said lower leg to resiliently grip the said exhaust tube, and a wedge member in the form of a readily-detachable clip secured to said lower leg and having a horizontal body portion spaced above said lower leg to be just above the flared upper end of the stem in said holder and abutting against the upstanding portion of said bracket which connects said legs, said body portion having deformable leg portions extending downwardly from opposite sides thereof and shaped to clip onto opposite sides of the lower leg of said bracket to the rear of the said slot therein, an abutment finger means located adjacent the path of movement of the holders and inwardly of the periphery of said carrier, and means to efiect a horizontal translational movement of said carrier in a direction to bring the exhaust tube of a stem in one of said holders into engagement with said abutment means to first tilt the stem so that its flare becomes wedged between the said lower leg of the holder and said wedge member and to crack ofi the said exhaust tube upon continuation of said translational movement of the carrier.

References Cited in the file of this patent 

